The present invention relates generally to the digital imaging arts, and, more specifically, with embedding a transformed digital image within the original digital image to authenticate the original digital image and to reconstruct the original digital image if the original digital image has been altered.
Images captured in electronic form can be easily copied, distributed, and even altered. It can be valuable to identify the integrity of an image. Regardless of how often a digital image is electronically copied or transferred, each digital copy should have embedded therein some indicia of authentication of the digital image.
With the advent of image editing software, the ability to manipulate or otherwise alter a digital image on a pixel by pixel basis is readily available. Thus, there is a strong need to be able to authenticate a digital image in order to determine whether or not the digital image has in fact been altered in some way.
One approach is to include information within the image which is normally not visible, but which can be detected if desired. This information can reveal image alterations.
U.S. Pat. No. 6,128,411 to Keith Knox entitled “Method For Embedding One Or More Digital Images Within Another Digital Image”, commonly assigned as the present application and herein incorporated by reference, teaches a method of combining a first digital image with a hidden embedded second digital image, typically a watermark, to serve as authentication for the first digital image. If the first digital image has been altered, then the second watermark digital image, once revealed, will also be altered. However, the Knox patent only serves to detect alteration of a digital image.
If the original data image has been altered, there is an equally strong need to reconstruct the original data image. Ideally, this reconstruction could be achieved from information embedded in the original data image, even if the original data image has been altered.
It is an object of the present invention to provide a hidden embedded second digital image within an original digital image to authenticate the original digital image and to reconstruct the original digital image if the original digital image has been altered.